The present invention relates to macromechanical closure elements for disposable articles such as diapers, training pants and incontinence pads. More particularly, the present invention relates to closure elements for disposable articles which are easy to use and manufacture.
Many different types of refastenable closure elements are known, including ties, pins, hook and loop systems, hook and eye systems, buttons, snaps, interlocking shapes, buckles, adhesive tapes, cohesive surfaces, and zippers and other slide connectors. Such fasteners have been used on a variety of products, both durable and disposable. Typical uses include envelopes, clothing, diapers, packages, footwear, construction closures, general attachment needs and feminine hygiene products.
Some fastening devices, such as hook and loop or adhesive tapes, require aligning an engaging surface with a landing surface. While this can result in an effective closure, it often results in misapplication and/or poor alignment of the elements being connected. Further, hook and loop fasteners can become ineffective due to compression and contamination or can harm surrounding materials. With an adhesive system, improperly fastening the device may render the entire product unusable. For example, in diaper applications, repositioning a tape tab which has been fastened improperly may result in tearing the outer cover of the diaper. Further, adhesive systems are prone to contamination-induced performance problems. In order to help prevent such problems, the use of these types of fasteners often require inefficient designs and extra material usage which can add to the cost of the products.
Other systems such as buttons, snaps, hooks and eyes, and ties are limited in that they connect discrete points only. If only one fastening device is used for a particular closure, the connection allows material around the fastener to rotate around the discrete points connected by the fastener. Further, if a span other than a single point needs to be connected, these systems generally require more than one fastening device per closure. Multiple connections can be cumbersome and can result in gapping between the discrete fastening device components, particularly if the connection is under stress. These systems also require precise alignment of the components to create the connection desired. Some point-to-point fastening systems require that forces be maintained on the system throughout the time the fastener is connected.
Other examples of interlocking closures can be found in U.S. Pat. Nos. 198,097; 207,253; 378,874; 771,719; 791,654; 2,837,096; 3,482,289; 3,620,180; 3,834,824 and 4,001,924. All of these fasteners can join lengths or spans, but each suffers from at least one important disadvantage, especially for use with disposable products like diapers. Some require the user to press on the connection to create engagement. Others require intricate manipulation to engage, such as tucking a tab over one element then below another. Yet others require at least one element to deform to create engagement, which may limit the load bearing capability of the fastener. Most lack provisions for allowing the fastener to conform to different shaped surfaces while in use and many of the systems have no provisions allowing for adjustable fit. Further, if used in disposable absorbent products such as diapers, these fasteners can cause skin marking and discomfort for the wearer.
To address these problems, U.S. Pat. No. 6,251,097 discloses a slot and tab closure design wherein the tab hinges are a xe2x80x9cTxe2x80x9d shape. The tabs are specifically designed for use on disposable diapers, bibs, wraps and packages, as well as sanitary napkins. The tabs taught in this patent contain a xe2x80x9clipxe2x80x9d portion, defined as that portion of the tab member 42 which is not joined directly to the underlying structure of the article to which the tab member is attached, and the lip portion lifts away from the underlying structure of the article so that it can be positioned in an overlapping configuration with at least a portion of an outboard portion of a slot member. This lip portion in the tab requires a complex product process as the lip is formed of a separate material attached to the underlying support substrate.
WO 97/02795 discloses a closure system on a diaper, which could also be considered a macro closure. The fastening means is comprised of two mutually co-acting first and second fastener elements and characterized in that the first or the second part of the fastener means includes a fastener portion which projects out in the circumferential direction of the waist band and which can be inserted into an opening in its associated second or first fastener element, and in that one of the first and the second fastener elements includes at least one locking member which extends in a direction generally perpendicular to the direction in which the fastener portion is inserted and co-acts with a locking aperture in the second fastener element when in the inserted position. The closure system requires complex three-dimensional shapes and would be difficult to manufacture and provide in a packaged form with multiple diapers.
U.S. Pat. No. 2,548,162 teaches a pinless diaper that uses what can be called a macro closure system. This system uses tabs and loops and the tabs are heart shaped and the widest part of the tab exceeds substantially in width the base portion (where the tab attaches to the diaper).
U.S. Pat. No. 5,545,159 teaches a disposable diaper with a type of macro closure wherein the macro closure comprises interlocking projections and receptacles. This system is also complex.
There is a need in the art for a macro closure system where the elements are easy to manufacture and use as well as can be packaged into a multi-article pack without creating uniformity problems due to the component having a three dimension shape.
The present invention is directed at an improved tab member for a closure system comprising a tab portion and a slot member. The slot member includes a slit or slot, with the slot located between an inboard portion and an outboard portion. The tab portion has a tab member having a length, an inner edge, an outer edge and at least one lip portion. The tab member outer edge is passed through the slot of the slot member to engage the fastening device. Once passed through the slot, at least one lip portion of the tab member overlaps or catches the outboard portion of the slot member to prevent the tab member from disengaging from the slot member. The slot member outward portion is retained between the lip portion(s) and an underlying tab substrate.
The improved tab portion of the present invention is a folded structure with at least one layer in common with the tab member and the tab substrate which carries the tab member. This provides a strong connection between the tab member and the tab substrate as the overall tab portion is substantially formed of a single substrate or laminate. The invention tab portion is also simple to manufacture using standard folding and laminating techniques.